<div class="tabs">
  <ul>
    <li><%= link_to '课程列表', {:action => 'syllabuses'},   class: "#{current_page?(all_syllabuses_path)? 'selected' : nil }" %></li>
    <li><%= link_to '全部班级列表',  {:action => 'courses'},  class: "#{current_page?(all_courses_path)? 'selected' : nil }" %></li>
    <li><%= link_to '未配置班级列表',  {:action => 'non_syllabus_courses'},  class: "#{current_page?(non_syllabus_courses_path)? 'selected' : nil }" %></li>
  </ul>
</div>